| a0 ' + ins≤(a, x0) = ins≤(a, y), a0 < a, a0 ∈ ins≤(a, y), ∀ a, y. ins≤(a, x0) = ins≤(a, y) → x0 = y ⊦ a0 ' + x0 = y |
⊦ x ≠ [] ∧ x.head < a → ins≤(a, x) = x.head + ins≤(a, x.tail)
a0 ' + ins≤(a, x0) = ins≤(a, y), a0 < a, a0 ∈ ins≤(a, y), ∀ a, y. ins≤(a, x0) = ins≤(a, y) → x0 = y ⊦ a0 ' + x0 = y, y ≠ [] ∧ y.head < a
a0 ' + ins≤(a, x0) = y.head + ins≤(a, y.tail), a0 < a, y.head < a, a0 ∈ y.head + ins≤(a, y.tail), ∀ a, y. ins≤(a, x0) = ins≤(a, y) → x0 = y ⊦ a0 ' + x0 = y, y = []
Used terms: y, a